Power-operated dogging mechanism



E. H. PERCY POWER OPERATED DOGGING MECHANISM May 14, 1929.

Filed May 29 1926 ATTORNEYS.

Vas

Patented May Y14, Y1929.

UNITED STATES.y

EDWIN 1r PERGY, oF roar BRAGGBI CALIFORNIA, ASSIGNOR, BY MESNE ASSfreriviinsir'rS,V f

PATENT OFFICE. c

TO THE PltESfJOCWIy COMPANY, A CORPORATION OF MICHIGAN.

,POWER-OPERATED DOGGING MECHANI'SM.

Application filed May 29,

This invention relates to power-operated clogging mechanism for sawmill carriages and has particular reference to what is termed tong dogs.l Such dogs consist ofa pair of dog arms mounted to swing toward and from each other ina vertical planefon the knee of a carriage, one dog engaging the topV of the log and the other engaging the bottom thereof. Bythis gripping of the top and bottoni of the log rather. than the Sides thereof, no injury is done to the backboard which is the term applied to the sawed face of 'the' log resting against the knee'. Such a mechanism'is disclosed in my co-pending application Serial No. 750,968iiled Nov. 20, 1924. The object of my invention herein is to provide an improved mounting for one of the dogs, whereby the same'engages and holds the log with greater facility. f

In the accompanying drawing, I have illustrated one specific embodiment of my invention, but it will be understood that they invention canbe otherwise embodied and that Y they drawing is not to be construed as defining or limiting the scope ofthe invention, the claims appended to thisv specification being relied upon for that purpose. y l

Referring to the figures of the drawing:

Figure'l isa side elevation of a knee of a sawmill carriage embodying my invention.

Figure 2 is a like view showing the dogs in another position. y

Figure 3 is a front view of the knee. l

Figure 4 is a fragmentary sectional Viewr taken on line IV-IV of Fig. 1. l f

The invention herein illustratedk includes a head block 10 and a knee 11. Asv in the usual v sawmill' carriage, the knee is slidable on the head block, its movements being controlled b y set Works and taper devices which form no part of the present invention. On the knee frame is `mounted a pair of dogs 12, which are termed tong dogs. The lower dog is pivotally mounted Von la pin 13, with a 'slotted connection so as to allow some end-l wise movement. The upper dog' is pivoted on a pin 14, which is carried by a pair of swinging arms 15 connected toa pin 13. Both dogs have a lug or boss 16 slidably working in a guide-way 17 on the knee. VVThis guide-way is vertically disposed and is curved at the upper end.l of theV knee, so that the upper dog will be retracted out of the wayof the log when not in use. There is a Spring or rubber bumper 18 at'the upper 1926. Serial No. 112,555.`

end of the guideway, forming a resilient Stop for the upper dog.

' The lower dog has toothed rack 19'piv- I otally connected to it, and this rack extends upjthrough a bifurcated portion in the upper dog, where it meshes with a pinion 2O `fixed upon a shaft 21 journaled lon said upper dog.

Thereis a relatively large spur gear 22 on the outerl end of this sha-ft, which meshes with a pinion 23 on the shaft of an electric motor 24, which motor is mountedupon the y upper dog and swings therewith.

y The rack 19 is guided andheld in mesh withthe pinion 2() by means of a pair of roll-y 'ers 25 engaging with theV rear edge of the rack and carried by a frame 25a. which is pivotally mounted on the shaft 2l. This form of i one resting at the bottom Vof the knee, and' the upper onepbeing in contact with the bumper 18 vand held in this position by suitable brakes on the motor.y When the motor is set inoperation'it causes the upperdog to descend along the rack,` and when-the upper xdog' strikes the log the lower 'dog will be pulledup'wardly by the rack. A frictional connection is provided as shown in my said co-pending application so that when bothV dogs are sufficiently engaged with the log. the

ging devices on a single'carriage, and allmo# n motor and spur gear 22 may continue to roj tors are under control of theset-works 'operl l ator. lVhen a log is rolled onto the carriage the set-works koperator closesthe switchv so as toset the motors inoperation in a directionto sink the `dogs into the log. After the dogs are Suiiiciently engaged with the log the motor and Spur gear 22 may continue to rotate, on account of the friction connection between s'aidfspur 'gear and the Shaft'21. This will prevent sudden jars and strains upon the motor, and the operator maycut out the motor at his leisure. Usually these motors are providedv with automatic brakes, so that after the dogs are engaged and the motors stopped,V accidental releasing of the dogs would be prevented. When the logis to be 'turned or taken olfv the carriage, the operal tor throws the 'switch so as to reverse the mo- Then the dogs reach the limit of movement permitted by the guide-way 17, the friction connection will again come into play, and allow the motor and spur gear 22 to rotate after the dogs have ceased to move. Thus the friction connection serves both in driv ing the dogs into the log and releasing them, and prevents sudden shocks to the motor., and generally reduces wear and tear on the entire mechanism.V

It will of course be understood that while I have herein illustrated the arms l2 as operated by an electricinotor, the same can in like manner be operated by substituting any oi various well known power means for the rack 19 and its cooperating mechanism.

The principal novelty ot my invention herein resides in so mounting the upper dog that it will engage the log at the proper angle and hold the same with greater security. The upper dog tooth 2G is carried byV a shoe 27 pivotally connectedV at its'upper end to th-e boss I6 on the free end of the upper arm 12 and having a lug or boss 28 at its lower end slidably engaging in the guideway I7. This connection permits swinging movement ot the member and tooth in accordance with the line of direction of the guideway 17. Thus, when a timber oit small diameter, as illus trated in Fig. l, is to be engaged, the tooth 26 is in a right angular position in the lower straight part ot the guideway. In such position, the dog engages the timber at the most ellective angle. When a large log isto be Y engaged, as shown in Fig. 2, the member 27 and tooth 26. are tipped backward by the curved upper portion ot the guidewayand the tooth engages the log more eective'ly. as will beseen and understood by referring to Fig. 2. i

The mode ofr carrying the tooth or spur 2G on the upper dog arm also provides against accidental release of the dog, should the log `start to roll away from the knee. In such an emergency the tendency would be to pull upwardly and outwardly on the spur, and this would cause the lugzor boss 28 to bind against the side of the guideway, and through the friction set up thereby, prevent the upperdog arm 'from being raised. y

Having thus described my invention, what I claim is:

l. Mechanism for clogging a log, comprising in combination a knee having a guideway therein extending vertically for a portion ot the way and curving rearwardly at the upper portion of the knee, a pair ol arms mounted for movement towards and from each other,

a dog carried by each arm, and means for pivotally connecting one of said dogs to its arm, said means comprising a shoe slidable in the guideway on the knee, and means for maintaining said shoe in alignment with the guideway. A

2. llIec-hanism 'orv clogging a log, comprising in combination a knee, having a guideway therein extending vertically for a portion of the way and curving rearwardly at the upper part ot' the knee, a pair of arms mounted tor movement towards and 'from each other, a dog carried by each arm, and a mounting for one of said dogs, comprising a shoe slidable along the guidewayoi the knee, a boss pivotally connecting said sho-e to the upper dog arm and slidable in said guideway, and a lsecond boss n the lower halt oi. said shoe and also slidable in said guideway whereby the said shoe is made to follow the course of the guideway in substantial.alinement therewith.

3. A clogging device comprising upper and lower dogs relatively movable on a. knee for gripping a log, actuating mechanism for the dogs having a connection with the upper dog permitting of relative pivotal movement thereof, means for constraining the upper dog to move lsubstantially parallel to the knee tace throughout the greater portion of its range of movement and causing it to tilt to an inclined position as it approaches the upper limit of its travel. v Y

i EDWIN H. PERCY. 

